In <uNksupB1#GA.450 at cpmsnbbsa02> "Ken Collins" <KPaulC at email.msn.com>
writes:
- - - - - - - -(snip) - - - - - - - - -
>in a way that i know of, he's correct. "memory" deficits are often
>correlated with the sensory/motor sites of lesions. one case i recall
is of
>a fellow who couldn't recall the verbal symbol "wrench"... there was
>cortical damage in the motor-hand "area". the idea is that he couldn't
form
>the memory of the verbal symbol for the hand tool be-cause the neural
>activation "state" that "normally" "addressed" the "memory" was
disrupted by
>there being a "hole" in it... the "meaning" was clouded beyond
recovery
>be-cause the appropriately-correlated activation could not occur in
>hand-motor cortex, which would "normally" be dominant when a "wrench"
was
>being used. yet, when tested on other aspects of the "same memory",
the
>fellow was successful.
>>this is an example of how "meaning" is "stored" and "retrieved" within
the
>brain.
>>do you see what i'm getting at [what i "mean"]?
>>no "memory" is "stored" in a precisely-localized way within the brain.
>rather, the bits and pieces that comprise it occur as tiny
modifications of
>the nerual circuitry corresponding to various aspects of one's
experience
>with this or that... and everything is "mapped" with respect to either
>sensory or motor activation, both experientially acquired.
>
>the "meaning" or "wrench" was dependent upon the motor activation
>underpinning the use of the tool within the fellow's experience.
Elizabeth Warrington (my speaker last November at the NY Academy of
Science joint meeting with NYNG) has for many years used patients with
odd dissociations (e.g. inability to name inanimate objects preseented
visually, vs. inability to name animate ones presented auditorally) to
develop a model of brain organization involving modalityXcategory
interactions. People have, indeed tried to explain some of these odd
cases in terms of relationships with broad modes of experience (e.g.
inanimate objects small enough to be manipulated vs. those too large
for this), and this makes plausible an involvement of areas related to
actions involving objects represented in "semantic" memory (this is the
current term for this type oof memory).
HOWEVER, I don't know if such memory deficits are "OFTEN" correlated
with plausibly specific "motor/sensory" sites. If you can give a
reference for the example you use, it wouod be helpful; one could
trace backwards (via the article's references) and forwards (via
Science Citation Abstracts) to see how oftern similar findings have
been reported.
(I think the discussion goes a bit down hill froom this good beginning,
so I'll leave it out)
F. LeFever
